Francis schumann



(No Model.)

P. SCHUMANN ROTARY VALVE.

N0.'309.,654. Patented Deo. Z3, 1884.

lllnrrnn Sti-rares Parent* @trice F i-ANGIS SCHUMANN, OF TRENTN, NEV JERSEY, ASSIGNOR OF ONE-HALE T() YV. D. HAVEN,

OF SAME' PLACE.

ROTARY VALVE.

LPECIFCATN orziing part or' Letters Fatemi'. No. 309,654-, dated December 23, 1884.

. Application lled June 34, 18S-1. (No model.)

To all wtom, il; muy concern:

Be it known that I, Farmers SCHUMANN, a citizen of the United States, residing at Treuton, in the count-y of Mercer' and State of New Jersey, have invented a new and useful Improvement'in Rotary Valves for Steam-Engines, of which the i'ollowingis a specification.

My invention relates to that class ot' valves in which the movement ofthe valve upon its axis places the cylinder in communication alternately with the live-steam duct and with the exhaust-chamber by means of chambers or passages formed in said valve. It relates more particularly to a novel arrangement of i5 the passages in valves of the above-mentioned class, by virtue of which arrangement the steam is admit-ted to the cylinder at such time and in such quantity as to act more efficiently and with greater economy than attends the use of rotary steam-engine valves as heretoiore constructed. The opening ofthe port to admit steam to the cylinder as effected by the axial movement of the valve is gradual. rlhe opening increases in size as the valve turns till it attains its maximum. The quantity of steam admitted per unit of angular movement also increases gradually to a maximum, being dependent upon the size of the admissionaperture. For the sake of convenience, I will term that movement of the valve during which steam is admitted to the cylinder' its stroke77 As ordinarily made, the valve admits steam in proportion to the distance it moves-that is to say, half of the steam during the first half of its stroke and the other hall" of the steam during the latter half of its stroke. lt is, however, desirable to admit a larger quantity of steam during the first part of the stroke of the valve and of the piston than during the latter part. To this endl have, in addition to the ordinary assage in the valve by which the cylinder is placed in communication with the steam-chest, provided the valve with a supplemental passage so arranged that during the first portion of the stroke, while a constantly-increasing amount of steam is entering the cylinder at one side of its port by the ordinary passage, an independent supply of steam of gradually-increasing amount may also enter said port at its other side by way of the supplemental passage. By a proper' arrangementof this passage any desired proportion of the steam-charge that is found most efficient may be delivered to the cylinder during the early part ofthe stroke of the valve and piston.

The above-described invention may be embodied in valves of various forms, and I do not therefore limit myselfto the exact construction shown in the accompanying drawings, in which, to make my invention more clearly understood, I have shown a method of carrying it into ei'lect.

3referring to the said drawings, Figure l is a sectional view of a valve and adjacent parts embodying my invention, the valve being about to begin what I have termedits stroke. 7 Fig. 2 is a similar view showing the valve as havin g performed about a quarter of its stroke.

A represents the body of the valve, which 7o moves in this casein the direction of the arrow l; B, a portion ofthe cylinder, having a port,

Z), with adjacent walls 'UZ/,- G, the steam-chest or live-steam duct, and D the exhaust-chamber. l have shown but one valve; but as ordi- 7 5. nai-ily used one of these valves will be situated at each end ot' the steam-cylinder, their axes in that case being transverse to the axis of the cylinder; or a single valve may be used, situated on the middle line of the cylinder.

c is the passage in the valve by which the cylinder is placed in communication with the steam-supply, and c that by which the cylinder and exhaust may be connected.

ai represents the supplemental steam-suppl y passage, opening at one side of the valve in proximity to the forward end of the passage a, from which it is shown as separated by a partition oi' about halt' the width of the cylinder-port b. At the other side of the valve 9o it terminates at such point that just before the passage a reaches the cylinder-port b the passage c2 is closed by a portion, c, of the surrounding casing, and just as the passage a begins to open into the port b the suppleg5 mental passage at begins to open into the steam-chest C.

The operation of the valve is as follows: Beginning with the position shown in dot-ted lines in Fig. l, it will. be seen that the cylinroo der and exhaust are in communication by means of the passage a, as indicated by the arrows 2, the supply-passages a a2 being cut oft from all communication, except with the steam-chest, by thewalls b and c. The valve movingin the direction of arrow l reaches the position shown in full lines, Fig. l, in which position the cylinder is cut off from the eX- haust and about to receive a supply of steam through the passages a a?, the valve being j ust at the beginning of its stroke.

Fig. 2 shows the valve as having performed the iirst quarter of its stroke, during which time the cylinder has received an amount of steam to deliver which by the passage a alone would have required nearly halt' of the stroke of-the valve. As the valve passes on, the passage a delivers an increasing amount of steam, while the passage a? continues to contribute to the supply until a point is reached, depending upon the arrangement ofthe passage at', where the wall bl cuts otf said passage.

From this point the supply is increased through the passage a till the port b rf leives the full capacity. The valve then moves to the first mentioned position. (Shown in dotted lines, Fig. l.) It will thus be seen that under the particular arrangement illustrated the port b, after the first quarter of the valvestroke, receives half of its whole capacity of steam instead of One-quarter of its capacity, as in rotary valves as heretofore made.

What I claim as my invention, and desire to secure by Letters Patent, is-

l. A rotary valve for steam-cylinders, having a main stearnsupply passage adapted to connect the cylinder and steam-chest, and a supplemental steamsupply passage, also adapted to connect the cylinder and steamchest during the period when said main passage is beginning to open, and to be subsequently closed while the main supply-passage remains Open, substantially as set forth.

2. A rotary valve for steam-cylinders, having a main steanrsupply passage adapted to connect the cylinder and steam-chest, and a supplemental steam-supply passage leading from the periphery of the valve at one point at which it receives live steam to the periphery of the valve at another point at which it delivers the steam to the cylinder, the said supplemental passage having a cut-oit Wall at the iirst-mentioned point, substantially as set forth.

3. A rotary valve for steam-cylinders, having a main steam-supply passage adapted to connect the cylinder and steam-chest, and a supplemental steam-supply passage leading from the periphery of the valve at one point at which it receives live steam to the periphery of the valve at another point at which it delivers the steam to the cylinder, the said supplemental passage having a cut-off wall at the two points mentioned, substantially as set forth.

ln testimony that l claim the foregoing I have hereunto set my hand in the presence Ot' two witnesses.

FRANCIS SCHUMANN. Witnesses:

RANDOLPH H. MOORE, WILLIAM OREILLY. 

